There are a wide variety of liquid collector and liquid distributor devices for use in gas-liquid exchange columns, such as a packed column. When separate collector-distributor devices are employed, the liquid collected by the collector is fed to a distributor for distribution of the liquid to a lower section of the column, which for example, may be a packed column having random or structured packing therein. The liquid-distributor device employed may be an orifice plate with gas risers, a trough or channel-type, or a tubular-type pipe distributor or other means of distributing the collected liquid. In one form of liquid distributor, there is a central feed trough with a plurality of lateral distribution channels extending outwardly from the sides of the central feed trough, the lateral distribution channels being fed by the central feed trough. Alternatively, the liquid distributor may comprise a plurality of spaced-apart, generally parallel lateral distribution channels extending substantially across the cross-sectional area of the column and being fed by one or more feed troughs positioned above the lateral distribution channels.
When separate collector and distributor devices are employed, typically the liquid becomes well-mixed as it flows to the feed box of the distributor device. However, in order to reduce column height and to save cost, integral collector-distributor devices rather than separate devices are employed; however, in such integral collector-distributor devices the liquid mixing may not be as efficient as in separate devices, and may, in fact, be poor, especially in large diameter columns, for example, over 10 or 12 feet in diameter.
One prior art collector-distributor device includes a centrally disposed central channel distributor, which is fed liquid by a downcomer from an overlying tray deck, and which includes a plurality of spaced-apart, generally parallel, channel distributors extending therefrom, and with the channel distributors placed below the tray deck, which is fitted with a plurality of gas risers, such as, for example, circular gas risers extending substantially across the cross sectional area of the tray deck and extending upwardly therefrom, generally uniformly dispersed above the spaces between the lateral channels of the distributor means below to permit the upward flow of gas through the tray deck. In such collector-distributors the gas risers therefore extend upwardly from the tray deck. The gas risers may include horizontal chimney hats or troughs over the top of the gas risers and spaced slightly apart therefrom to prevent descending liquid from falling through the risers, and to bring the collected liquid to the tray surface so that it can be delivered to the central channel of the underlying distributor means via a downcomer extending downward from the tray deck. When the gas risers are individual, circular gas risers, the chimney hats may be circular hats placed over each gas riser; however, where the gas risers are rectangular-type gas risers, the chimney hats may include elongated rectangular chimney hats or troughs which are generally extended over the top surface of the rectangular risers or over a row of circular risers and are generally rectangular trays with upturned edges, which are horizontal, that is, parallel to the main collecting tray surface, which direct collected liquid to the main collecting surface.
Another prior art collector-distributor device is illustrated and described in a 1989 Koch Engineering Company, Inc.'s "Packed Tower Internals" publication, wherein a liquid distributor is shown with circular gas risers and flat, horizontally aligned rectangular chimney hats which are generally spaced over the top surface of the circular risers.
It is desired to provide for a new, integral collector-distributor device for use in a gas-liquid exchange column, to promote selected radial distribution of a collected liquid on a tray surface, to avoid liquid concentration gradients across the tray surface and to provide a system including such integral liquid distributor-collector devices and a method of promoting radial dispersion of liquid and preventing liquid concentration gradients across the tray surface without impeding the upward flow of gas in the column.